For polystyrene foam, I use UHU Por (not sure what the chemical is), it makes it brand new. I have an EPP wing that I crashed three times and broke into pieces, and Por makes it brand new again.
The bond that failed was PLA to PLA (I 3D-printed a soap holder, so the surface wasn't very smooth either). I don't know if it was the water or if I didn't apply enough glue or what.
The bond that failed was PLA to PLA (I 3D-printed a soap holder, so the surface wasn't very smooth either). I don't know if it was the water or if I didn't apply enough glue or what.